In the personal computer field, especially in lap tops and other portables, but also in desk units, space and weight are often of significant importance. Over the years, computer peripheral makers have constantly reduced the size of storage media and the devices with which they are used. A good example is in removable storage media such as floppy or flexible disk drives, where the media were originally 8" in diameter, then reduced to 5-1/4", and subsequently reduced to 3-1/2", while the drives started as "full height" and then went to "half height" for a 5-1/4" or 3-1/2" port. In desk top computers, 3-1/2" peripherals are often mounted on a 5-1/4" half height port. In lap tops, notebooks and other portable computers, available space is at a particular premium, so that a different emphasis has been adopted, namely, approaching the objective of "just media size", in the drive unit. This means that the drive unit has the smallest feasible envelope around the full media. With the 3-1/2" floppy disk, the envelope is approximately 4".times.4" to 4".times.6", in depth and width, and the height (or thickness) is often 1/2" or less.
Since a lap top may only be 10" to 14" wide and 8" to 10" deep, however, it can be seen that a 4".times.4" to 4".times.6" envelope size demands use of a substantial internal volume within the lap top even if of low height. Reduction of this size requirement can be highly desirable, but a drastic reduction has not heretofore been achieved, except in terms of reducing profile height.
In modern recording systems, the tendency has been to try to secure higher capacity by increased record track density, increased recording density, or reduction of the overall size of the media as well as the drives with which they are used. However, media size is substantially invariant for a long time, once a standard size has been accepted by the industry and put widely into use. Thus software, documents and data are recorded and transferred on floppy disks now predominantly of the 3-1/2" standard, and no substantial changes are foreseen for the immediate future. Consequently, for the numerous data handling systems and devices on the market in which space is at a premium, a "smaller than media size" drive can be of great utility. As improvements in capability and reductions in size continue, this prospect will significantly increase.
Similar considerations apply to other removable storage media, such as CD-ROMS, Magneto-Optical (MO) and Bernoulli disks. Although different design factors exist, the volumetric improvement should be achievable in the same conceptual manner. For example, a higher density magnetic disk cartridge, known as the ZIP drive, is now being widely accepted because of its capacity and shorter access times, and while it is driven from a central hub, access to the two sides of the disk is gained through an access door in the inserted end. The cartridge is of approximately 4".times.4" to a side, but only 1/4" high, so that a separate or integral drive housing substantially larger in volume than the medium has heretofore been used.